The rapid expansion and scale of development associated with the Athabasca oil sands industry has generated concerns regarding potential contamination of the surrounding watershed from industry-derived contaminants. While research to date has demonstrated pathways of exposure through atmospheric deposition and reclamation of oil sands process water, our understanding of how fish in the Athabasca watershed are impacted by these activities are not as well understood. The objective of this Show moreThe rapid expansion and scale of development associated with the Athabasca oil sands industry has generated concerns regarding potential contamination of the surrounding watershed from industry-derived contaminants. While research to date has demonstrated pathways of exposure through atmospheric deposition and reclamation of oil sands process water, our understanding of how fish in the Athabasca watershed are impacted by these activities are not as well understood. The objective of this dissertation was to determine whether population performance of fishes in the Athabasca watershed have the potential to be impacted by oil sands development. This was assessed by evaluating the impacts of a proposed tailings reclamation strategy (i.e., the creation of end pit lakes) on fish population performance, and by evaluating the current performance of fish in the Athabasca River. White Sucker were selected as the model organism for this work based on their regional availability, spawning period, size, and role as a sentinel species in effects-based monitoring programs. Population performance was evaluated using effects-based indicators of growth, energy storage and reproductive performance in adult fish, as well as survival and rates of deformity in early life stages. Effects were then interpreted in relation to biochemical and chemical indicators of contaminant exposure. Potential estrogenic and androgenic effects were evaluated using a recombinant yeast assay. White Sucker in the Athabasca watershed exhibit effects consistent with metabolic disruption. Biochemical endpoints suggest exposure to atmospherically derived polycyclic aromatic hydrocarbons may be a contributing factor to these effects. Naphthenic acids were detected in the Athabasca watershed at concentrations below thresholds known to cause impacts on growth or reproduction. Water samples collected from the watershed showed no evidence of (anti-) estrogenic or (anti-) androgenic activity at ecologically relevant concentrations, and no impacts on survival, or rates of deformity in early life stages of White Sucker exposed to this material were evident. Show less